The monoester method has been used in the synthesis of sucralose. Converted to sucrose-6-ester from sucrose, sucralose-6-ester is generated through chlorinating sucrose-6-ester. Sucralose is prepared through alcoholysis of sucralose-6-ester by using sodium methoxide/methanol or sodium ethoxide/ethanol. The commonly used chlorinating reagent is a Vilsmeier reagent, which was usually prepared through reacting DMF with phosgene or with thionyl chloride. A major drawback of such methods is the amount of sulfur dioxide emitted through chlorination which leads to increase treatment procedures and requirements for equipment. Further because phosgene is a strongly toxic gas, it is not suitable to store, transport and use.
Accordingly there is a need in the art for an improved method making sucralose at high yield with less toxic by products.